Whereas normally documents, which is understood to mean flat materials and written matter of random type, are fed as individual sheets or stacks to a document shredder, it frequently arises that entire stacks of flat material webs in the form of folded layers, e.g. printouts from data processing equipment, have to be destroyed as a result of their confidentiality. However, shredders are not always designed to be able to shred such stacks into small pieces.